@fluidframework/core-utils

@fluidframework/core-utils

This package is intended for sharing and promoting best-practice implementations of Fluid-agnostic utility functions across packages in the Fluid Framework repo.

Using Fluid Framework libraries

For a dependency on a Fluid Framework library's public APIs, we recommend a ^ (caret) version range. For example, use ^1.3.4.

For a dependency on an unstable API, such as a beta API, we recommend a more restrictive version range. For example, use a ~ version range.

Installation

Run this command to install the package:

npm i @fluidframework/core-utils

Importing from this package

This package uses package.json exports to separate APIs by support level. For information about the support guarantees, read API Support Levels.

Import the public APIs from @fluidframework/core-utils.

Import the beta APIs from @fluidframework/core-utils/beta.

Import the alpha APIs from @fluidframework/core-utils/alpha.

Import the legacy APIs from @fluidframework/core-utils/legacy.

API Documentation

Read the @fluidframework/core-utils API documentation at https://fluidframework.com/docs/apis/core-utils.

Adding code to this package

As a utility package, this package does not have a strong identity. This means that it's easy to become a "dumping ground" for code that we think we should share but doesn't have an obvious home. We try to avoid dumping things into utility packages, and this one is no exception.

New code should only be added to this package in rare circumstances. In most cases, the code would be better placed in a package with a clear identity (e.g. an "events" package for shared event infrastructure) or not shared at all.

Requirements

This package has important requirements for the code within it.

1. Code in this package must have zero dependencies. That is, it must not depend on other packages, even within the Fluid Framework repo. devDependencies are OK.
2. All exports must be designated @internal. This code is intended for use within the Fluid Framework only.
3. This package should only contain 'implementation' code, not type definitions. This is the most flexible rule, and there are some exceptions. If the type is only necessary when using this package, then it is probably OK. However, usually such types would be better placed in core-interfaces or in a package that corresponds to the purpose.

If you want to add code that does not meet these requirements, these other packages may be a better choice:

• Types and interfaces that are intended to be broadly shared across the client release group should be put in the core-interfaces package.
• Shared implementation code with dependencies should be put in the client-utils package.

Minimum Client Requirements

Fluid Framework client libraries support the platforms in this document. These requirements are intentionally restrictive. Within a major version series, we can relax these requirements, but we cannot make them stricter. For a Long Term Support (LTS) version, we might need to support these platforms for several years.

Other configurations can work, but Fluid Framework does not support them. If an unsupported configuration stops working, we do not classify this as a bug. To request support for a configuration that is not listed, file an issue. The product team will evaluate your request. In the issue, specify the current status of the configuration:

• The configuration works but needs official support.
• The configuration does not work and requires changes.

Supported Runtimes

• Fluid Framework supports Node.js versions 22 and 24 while they receive upstream support.
  • Fluid Framework will stop support for version 22 when upstream support ends on 2027-04-30.
  • Fluid Framework does not support Node.js with the --no-experimental-fetch flag.
• Fluid Framework supports modern browsers that support the ES2022 standard library.

Supported Tools

• TypeScript 6.0:
  • Fluid Framework supports all strict options.
  • Set the build targets (lib, target) to ES2022 or later.
  • Enable strictNullChecks.
  • Fluid Framework does not support configuration options deprecated in TypeScript 6.0.
  • Fluid Framework does not fully support exactOptionalPropertyTypes. If you enable this option, do not use in, Reflect.has, Object.hasOwn, or Object.prototype.hasOwnProperty to narrow members of Fluid Framework types. These methods can incorrectly exclude undefined from the possible values.
• webpack 5
  • We do not require a specific bundler. Other bundlers that handle ES Modules can work, but we actively test only webpack.

Module Resolution

In TypeScript compilerOptions, use Node16, Node20, NodeNext, or Bundler module resolution. These settings follow the Node.js v12+ ESM Resolution and Loading algorithm.

Do not use Node10 module resolution.

Module Formats

• ES Modules: Use ES Modules to consume Fluid Framework client packages, including in Node.js.
• CommonJS: Fluid Framework does not officially support CommonJS in version 3.0 or later.

Contribution Guidelines

You can contribute to Fluid Framework in these ways:

• Answer questions in GitHub Discussions.
• Submit bug reports and help verify fixes.
• Review source code changes.
• Contribute bug fixes.

For detailed instructions, read the repo documentation.

This project follows the Microsoft Open Source Code of Conduct. For more information, read the Code of Conduct frequently asked questions. For questions or comments, contact opencode@microsoft.com.

This project may contain Microsoft trademarks or logos for Microsoft projects, products, or services. Use of these trademarks or logos must follow Microsoft’s Trademark & Brand Guidelines. Use of Microsoft trademarks or logos in modified versions of this project must not cause confusion or imply Microsoft sponsorship.

Help

Read the Fluid Framework documentation for information about Fluid Framework concepts and APIs.

To request information that the documentation does not contain, create an issue.

Trademark

This project may contain Microsoft trademarks or logos for Microsoft projects, products, or services.

Use of these trademarks or logos must follow Microsoft's Trademark & Brand Guidelines.

Use of Microsoft trademarks or logos in modified versions of this project must not cause confusion or imply Microsoft sponsorship.